Abstract
Photosynthetic rate is one of the key factors limiting yield of cotton. Reactive oxygen species (ROS) generated by abiotic stress imposes numerous detrimental effects and causes tremendous loss of yield. It is worth to study whether ROS scavenging enzymes could affect yield through regulating photosynthetic rate in cotton. In this study, we created transgenic cotton with changes of endogenous ROS by overexpressing or suppressing the expression of cytosolic ascorbate peroxidases (APXs), which are hydrogen peroxide (H2O2) scavenging enzymes in plants. The suppression of cytosolic APXs by RNAi brings about a great influence on plant growth and development. Plant height and leaf size declined, and yield-related traits including single boll weight, seed weight, seed size, and lint weight dropped significantly, in IAO lines (cytosolic APX-suppressed lines). The stunted plant growth was due to the decrease of plant photosynthetic rate. The evidences showed that increased ROS level in guard cells inhibited stomatal opening and suppressed the absorption of CO2 and H2O in IAO line. The decrease of water content and the increase of water loss rate in leaf exacerbated the decline of photosynthetic rate in cytosolic APX-suppressed lines. Based on these results, it implies that cytosolic APXs as a whole play an important role in maintaining REDOX balance to regulate photosynthetic rate and yield in cotton.
Highlights
Photosynthesis refers to the process in which leaves use light energy to change the absorbed carbon dioxide and water into sugar and release oxygen in green plants
We explored the role of cytosolic APX (cAPX) in protecting cellular oxidative homeostasis of stomata guard cells and the function to maintain photosynthesis in cotton
The stomatal opening in IAO lines was smaller than that in wild-type plants (Figure 4A). These results suggested that the decrease of cAPX expression in leaves increased Reactive oxygen species (ROS) level in stomatal guard cells, leading to the decrease of stomatal aperture, which might decrease the supply of carbon dioxide and water used for photosynthesis
Summary
Photosynthesis refers to the process in which leaves use light energy to change the absorbed carbon dioxide and water into sugar and release oxygen in green plants. It is the primary producer of organic matter and energy on earth. Photosynthetic efficiency plays a critical role in crop production and is an important factor limiting crop yield (Zhu et al, 2010). High photosynthetic efficiency is an important indicator of high yield in crops (Evans, 2013). There is great potential to improve the photosynthetic efficiency for high yield production in crops
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